From: "M. Edward (Ed) Borasky" <znmeb@...>
Date: 2006-04-11T23:21:31+09:00
Subject: Re: Possible RubyQuiz idea

OK ... here's my nomination for a RubyQuiz challenge. I've posted a 
couple of hints, but I'm pretty sure there could be at least 15 unique 
solutions.

Given a rectangular matrix, compute its singular value decomposition.

Now, there are a lot of variants just on the problem specification 
alone, such as whether the matrix is sparse or dense, whether it fits in 
real memory or not and whether you need all of the singular values and 
vectors. And there are a lot of variants on the solution methods -- 
"pure Ruby" or interfacing to an existing C library, etc.

So let's say "pure Ruby" -- no external software in any language. And 
let's specify the most general case -- a large sparse "out of core" 
solver. The algorithms are in

http://www.netlib.org/tennessee/ut-cs-93-194.ps

The challenge then becomes to create the most *efficient* implementation 
in pure Ruby. So ... hacking Ruby itself *is* allowed, as is hacking 
and/or "developing" the virtual machine or swapping in a new one.

Hal Fulton wrote:
> This might be too easy, it's JEG2's call.
>
> Read in an ordinary crontab file and print out a list of
> jobs that will run in the next N minutes.
>
> Just a thought.
>
>
> Cheers,
> Hal
>
>
>

-- 
M. Edward (Ed) Borasky

http://linuxcapacityplanning.com